From 3f6f1480d86bf9fc16c160d803ab1d006e3058d5 Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Mon, 13 Oct 2014 13:04:14 +0300 Subject: [PATCH] KVM: x86: PREFETCH and HINT_NOP should have SrcMem flag The decode phase of the x86 emulator assumes that every instruction with the ModRM flag, and which can be used with RIP-relative addressing, has either SrcMem or DstMem. This is not the case for several instructions - prefetch, hint-nop and clflush. Adding SrcMem|NoAccess for prefetch and hint-nop and SrcMem for clflush. This fixes CVE-2014-8480. Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5 Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 97da5034d812..749f9fa38254 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3807,7 +3807,7 @@ static const struct opcode group11[] = { }; static const struct gprefix pfx_0f_ae_7 = { - I(0, em_clflush), N, N, N, + I(SrcMem | ByteOp, em_clflush), N, N, N, }; static const struct group_dual group15 = { { @@ -4024,10 +4024,11 @@ static const struct opcode twobyte_table[256] = { N, I(ImplicitOps | EmulateOnUD, em_syscall), II(ImplicitOps | Priv, em_clts, clts), N, DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N, - N, D(ImplicitOps | ModRM), N, N, + N, D(ImplicitOps | ModRM | SrcMem | NoAccess), N, N, /* 0x10 - 0x1F */ N, N, N, N, N, N, N, N, - D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM), + D(ImplicitOps | ModRM | SrcMem | NoAccess), + N, N, N, N, N, N, D(ImplicitOps | ModRM | SrcMem | NoAccess), /* 0x20 - 0x2F */ DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read), DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read),